Per-Olov Löwdin
Encyclopedia
Per-Olov Löwdin was a Swedish
physicist
, professor at the University of Uppsala from 1960 to 1983, and in parallel at the University of Florida
until 1993.
A former graduate student under Ivar Waller
, Löwdin formulated in 1950 the symmetric orthogonalization scheme for molecular orbital
calculations. This scheme is the basis of the zero-differential overlap (ZDO) approximation used in semiempirical theories.
He is also credited with the use of fat symbols for matrices
, making easy the derivation of several theorems of quantum mechanics
.
The famous 'Löwdin's pairing theorem' used in ROHF, UHF
and RES-GVB
theories is not his. According to himself, George G. Hall
and King made the formal proposition after an informal suggestion by Löwdin.
His partitioning technique for quantum chemistry
problems is best appreciated through the series of 14 papers on perturbation theory
published between 1963 and 1971.
He was also a very active teacher, starting the Summer Schools of Quantum Chemistry at Uppsala around 1958. In 1959-1960 Löwdin started the Quantum Theory Project at the University of Florida as a sister project to the Uppsala Quantum Chemistry Group. In 1964 he was joined by John C. Slater
from MIT. The International Winter Institutes (held initially at Sanibel Island, and later at Gainesville) provided the initiation of hundreds of Latin American young scientists during the eighties and nineties. In 1960 he founded the Sanibel Symposium
in conjunction with the Winter Institute. They have been held every year since 1960 with the 47th symposium held in 2007.
Löwdin was elected a member of the Royal Swedish Academy of Sciences
in 1969 and was a member of the committee for the Nobel Prize in Physics
from 1972 to 1984. He was the founder of the International Journal of Quantum Chemistry
and of the series Advances in Quantum Chemistry. He was a foundation member of the International Academy of Quantum Molecular Science
.
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
, professor at the University of Uppsala from 1960 to 1983, and in parallel at the University of Florida
University of Florida
The University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
until 1993.
A former graduate student under Ivar Waller
Ivar Waller
Ivar Waller was a Swedish professor of theoretical physics at Uppsala University. He developed the theory of X-ray scattering by lattice vibrations of a crystal, building upon the prior work of Peter Debye...
, Löwdin formulated in 1950 the symmetric orthogonalization scheme for molecular orbital
Molecular orbital
In chemistry, a molecular orbital is a mathematical function describing the wave-like behavior of an electron in a molecule. This function can be used to calculate chemical and physical properties such as the probability of finding an electron in any specific region. The term "orbital" was first...
calculations. This scheme is the basis of the zero-differential overlap (ZDO) approximation used in semiempirical theories.
He is also credited with the use of fat symbols for matrices
Matrix (mathematics)
In mathematics, a matrix is a rectangular array of numbers, symbols, or expressions. The individual items in a matrix are called its elements or entries. An example of a matrix with six elements isMatrices of the same size can be added or subtracted element by element...
, making easy the derivation of several theorems of quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
.
The famous 'Löwdin's pairing theorem' used in ROHF, UHF
Unrestricted Hartree-Fock
Unrestricted Hartree–Fock theory is the most common molecular orbital method for open shell molecules where the number of electrons of each spin are not equal...
and RES-GVB
Generalized valence bond
The generalized valence bond method is one of the simplest and oldest valence bond method that uses flexible orbitals in the general way used by modern valence bond theory. The method was developed by the group of William A...
theories is not his. According to himself, George G. Hall
George G. Hall
George Garfield Hall , is an applied mathematician and scientist of distinction, known for original work and contributions to the field of Quantum chemistry....
and King made the formal proposition after an informal suggestion by Löwdin.
His partitioning technique for quantum chemistry
Quantum chemistry
Quantum chemistry is a branch of chemistry whose primary focus is the application of quantum mechanics in physical models and experiments of chemical systems...
problems is best appreciated through the series of 14 papers on perturbation theory
Perturbation theory
Perturbation theory comprises mathematical methods that are used to find an approximate solution to a problem which cannot be solved exactly, by starting from the exact solution of a related problem...
published between 1963 and 1971.
He was also a very active teacher, starting the Summer Schools of Quantum Chemistry at Uppsala around 1958. In 1959-1960 Löwdin started the Quantum Theory Project at the University of Florida as a sister project to the Uppsala Quantum Chemistry Group. In 1964 he was joined by John C. Slater
John C. Slater
John Clarke Slater was a noted American physicist who made major contributions to the theory of the electronic structure of atoms, molecules and solids. This work is of ongoing importance in chemistry, as well as in many areas of physics. He also made major contributions to microwave electronics....
from MIT. The International Winter Institutes (held initially at Sanibel Island, and later at Gainesville) provided the initiation of hundreds of Latin American young scientists during the eighties and nineties. In 1960 he founded the Sanibel Symposium
Sanibel Symposium
The Sanibel Symposium is an international scientific conference in quantum chemistry, solid-state physics, and quantum biology. It has been organized by the Quantum Theory Project at the University of Florida in Gainesville, Florida, Florida every winter since 1960. It was founded by Per-Olov...
in conjunction with the Winter Institute. They have been held every year since 1960 with the 47th symposium held in 2007.
Löwdin was elected a member of the Royal Swedish Academy of Sciences
Royal Swedish Academy of Sciences
The Royal Swedish Academy of Sciences or Kungliga Vetenskapsakademien is one of the Royal Academies of Sweden. The Academy is an independent, non-governmental scientific organization which acts to promote the sciences, primarily the natural sciences and mathematics.The Academy was founded on 2...
in 1969 and was a member of the committee for the Nobel Prize in Physics
Nobel Prize in Physics
The Nobel Prize in Physics is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others are the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and...
from 1972 to 1984. He was the founder of the International Journal of Quantum Chemistry
International Journal of Quantum Chemistry
The International Journal of Quantum Chemistry is an international peer-reviewed scientific journal publishing original, primary research and review articles on all aspects of quantum chemistry, defined as "Theory and Computation in Chemistry, Physics, and Molecular Biology". The impact factor of...
and of the series Advances in Quantum Chemistry. He was a foundation member of the International Academy of Quantum Molecular Science
International Academy of Quantum Molecular Science
The International Academy of Quantum Molecular Science is an international scientific learned society covering all applications of quantum theory to chemistry and chemical physics. It was created in Menton in 1967. The founding members were Raymond Daudel, Per-Olov Löwdin, Robert G. Parr, John...
.
Publications
External links
- Jan Linderberg, Biographical Memoir, Proc. Am. Phil. Soc. 147 (2) (2003)
- Kimio Ohno Early Ideas in the history of Quantum Chemistry (1976)
- Per-Olov Löwdin Short Curriculum Vitae
- The Löwdin Lectures, Uppsala University
- Quantum Theory Project founded by Löwdin at the University of Florida in 1960